Spring-scale.



N@.s4s,v4 0. .PATENTED APR.2,1907.

H. HANSEN.

SPRING SCALE.

APPLIOATION FILED JUNE 29. 1905.

onirnn STATES PTE SPRING-SCALE.

Specification of Letters Patent.

Patented April 2, 1907.

Application filed June 29, 1905. Serial No. 267.587.

To all whom it may concern.-

Be it known that I, MARIUs H. l-IANsEN, a citizen of the United States, residing at Chicago, in the county-of Cook and State of Illinois, have invented certain new and useful Improvements in Spring-Scales, of which the following is a specification.

The resent invention relates to springscales of the depending or hanging type, and more particularly to that subclass of such scales in which the movement of the drawbar under the influence of the load is resisted by a single coiled spring.

Generally stated, the object of the present invention is to provide an improved scale of this class.

In order to obtain accurate results, it is essential, among other things, that the moving parts be free from faccidental or .-.unprovided-for friction, by which is meant, for example, the friction of the draw-bar with the case due to accidental and unintended tortional or lateral strains upon the draw-bar. Friction thus produced not having been taken into account in the adjusting of the scale and being subject to variations under varying conditions results in inaccuracies. One of the specific objects of the invention is, therefore, to eliminate this accidental friction.

Another specific object of the invention is to provide a draw-bar of improved construction which may be used in scales having either one or a plurality of springs.

To these ends the invention consists in the features of novelty that are hereinafter decured to said sides.

scribed with reference to the accompanying drawings, which are made a part hereof, and in which Figure1 is a front elevation of a scale embodying the invention, the face-plate of the case including the dial-box and dial being indicated by dotted lines. Fig. 2 is a vertical section thereof on the line 2 2, Fig. 1, looking in the direction of the arrow. Fig. 3 is a horizontal section on the line 3 3, Fig. 1, looking downward. Fig. 4. is a detail.

The case comprises a back 1, sides 2, top 3, bottom 4, and front 5 6. The section 5 of the front comprises the circular back 5 of the dial-box and is provided with openings for the reception of the ears 7 on the sides 2, by which the said back of the dial-box is se- The section 6 of the front has at top a vertical extension 8, terminating in a horizontal branch 9, which is I split to receive the front edge of a lug 10,

rising from the top 3. The details in the construction of the top need not be here gone into. Suffice it to say that it has an opening through which passes a screw 11, the lower end of which is attached to the upper end of the single load-spring 12. Onto this screw is turned a nut 13, which is supported by the The spring terminates at its lower end in a I hook 16, which engages in the manner resently to be described the upper end o the draw-bar 17, the lower end of which projects through an opening 18 in the bottom 4 of the case and has a scale-pan attached to it by any,

suitable means-as, for example, a hook 19.

The upper end of the draw-bar has a horizontal forwardly-extending offset 20, from the forward end of which depends a lip or flange 21. At one end the portion 20 is slit to provide an car 22, and this ear is bent downward into parallelism with the adjacent portion of the lip 21. The two are perforated, as at 23, for the passage of the pin 24, by which a rack-bar 25 is pivotally supported, so as to be ca able when unrestrained of swinging freely a out the pivot. This rackbar is normally in engagement with a pinion 26 on the shaft 27, which carries the pointer 28. The pinion is confined in a housing 29, which is secured to the back of the dial-box by screws 30. One of these screws is located at such distance from the pinion that it will prevent the rack from moving laterally out of engagement with the pinion under sudden shocks or impulses. It is not, however, sufficiently close to be constantly in contact with the back of the rack, the rack being held in engagement with the pinion normally by means of an arm 31, which performs the double duty of a weight and a stop. As a weight it tends constantly to hold the rack in engagement with the pinion. As a stop it will engage the side of the case, and thereby prevent any considerable lateral movement of the upper end of the draw-bar in its direction. The draw-bar is made of a piece of sheet metal, preferably steel, embossed for the purpose of increasing its rigidity. Near its lower end and at a distance from the bot tom of the casing representing the maximum extension of the spring it is provided with a shoulder 32, which is adapted to serve as a stop when brought into contact with the bottom of the casing for limiting the further movement of the draw-bar. It is also ol'iset, as at 33, in order to provide room in front of it for the housing 2-9. Its o'l'l'set portion 20 is provided with a slot 3 1, and its vertical portion is provided adjacent to said o'll'set portion with a perforation 35 for receiving the hook 16. The object of the slot 34 is to provide shoulders that engage the sides of the hook 16, and thereby compel the drawbar to at all times occupy a fixed relation to the hook-that is to say, assuming that'the hook stands in a vertical plane which is parallel with the sides of the case the described engagement of the hook with the draw-bar will compel the draw-bar to stand in a plane perpendicular to the plane aforesaid-e. 6., parallel with the back of the case. When in this position, it may move freely through the opening 18 without any or any considerable frictional contact with the sides thereof. It will be observed that the hook is angular. The object of this is to compel the draw-bar to at all times seat itself at the lowermost point of the top side of the hook, or, in other Words, directly in the angle formed by the front and back of the hook. This prevents the draw-bar from riding up on the hook, the result of which would be a greater or less disturbance of the relations of the parts. It is apparent that the position of the draw-bar with relation to the casing being fixed by the position of the slot 18 it is necessary to provide some means for bringing the hook to the proper position with relation to the drawbar. This is done by turning the spring about its axis in one direction or the other, as may be necessary, and for this purpose a fork 36 is pivoted to the top of the case by some suitable means as, for example, by rivet 37. This rivet enables the movement of the fork in one direction or the other and is sufliciently tight to maintain the position of the fork when once set. The fork engages the upper extremity 38 of the spring, so that when the fork is turned about the pivot 37 the spring will be turned about its axis.

The point of suspension of the spring, the point of attachment of the spring to the draw-bar, and the point of suspension of the load from the draw-bar are in a straight line whichmay be called the line of strain. This line passes through the draw-bar from end to end, so that a portion of the draw-bar is on each side of it. It will be observed, however, that upon the side opposite that on which the rack-bar 25 and weight 31 are located the metal of the draw-bar itself is of greater preponderance. This is for counterbalancing purposes and for insuring the maintenance of the three points aforesaid in a straight line. The arrangement has the further advantage of enabling the draw-bar to be placed. behind the pinion instead of at one side thereof, in which latter case it is necessary to form it with an offset.

As before described, the position of the hook 16 tends to control the position of the draw-bar; but it cannot do this absolutely, because the spring is elastic. Any considerable twisting of the draw-bar, such as would cause the rack-bar and pinion to bind, is prevented by the walls of the narrow slot 18 in the bottom of the case engaging the broad but narrow lower end of the draw-bar.

1 am aware that it has been proposed to provide various means for preventing the twisting of the lower ends of draw-bars of substantially rectangular shape, but I am not aware that it has ever been proposed to make the lower end of the drawbar of considerably greater width than thickness and pass it through a narrow elongated slot in the bottom of the case.

l/Vhat I claim as new, and desire to secure by Letters Patent, is-

l. A spring-scale having in combination a case having an opening in its bottom and a single spring supported by the case, a drawbar made of a broad piece of sheet metal, the upper end of said draw-bar being bent downward, the two sides of said bent portion being perforated at one side of the longitudinal center of the draw-bar, a hook secured to the lower end of the spring and occupying said opening, a rack pivoted to the draw-bar, a pointer and means for transmitting movement from the rack to the pointer, substantially as set forth.

2. A spring-scale having in combination a case, a spring supported by the case, a drawbar made of sheet metal, and having at its upper end two downward ly-turned portions, a rack-bar, the upper end of which occupies the space between said downwardly-tunled portion, and is pivoted thereto substantially as described.

3. A spring-scale having a case, a spring, the upper end of which is supported by the case, an adjustable fork engaging the upper end of the spring, and a draw-bar, the lower end of the spring being provided with means for engaging the draw-bar, substantially as described.

4. In a spring-scale, the combination of a case, a spring supported by the case an d having at its lower end a hook, a draw-bar made of sheet metal and having its upper end bent first horizontally and then downwardly, the top of said bent portion having an elongated opening and the adjacent portion of the draw-bar having an opening, through which openings the hook of the spring passes, and a rack pivoted to the aforesaid downwardlyextending portion, substantially as described.

5. A spring-scale having in combination a case, a spring supported thereby, a draw-bar supported by the spring, means carried by the draw-bar for supporting the load, a rackbar carried by the draw-bar, a pinion with which the rack-bar engages, and a weight for holding the rack-bar in engagement with the pinion, said Weight being adapted to contact with the side of the case for limiting the lateral movement of the upper end of the drawbar, substantially as described.

6. A draw-bar for scales made of a single piece of sheet metal, having its upper end bent to provide a horizontal portion and a vertical depending portion, a portion of the With openings, a spring having flattened hook passing through said openings and a rack-bar pivoted between the two vertical depending portions, substantially as described.

MARIUS H. HANSEN.

Witnesses:

D. M. HOPKINS, WILLIAM J. HANSEN. 

